"The art of ensuring that, to as large an extent as possible, facilities (such as, for example, Web access) are available to people whether or not they have impairments of one sort or another." (Tim Berners-Lee, "Weaving the Web", 1999)
"Accessibility is a subfield of human-computer interaction and deals with users with deficiencies. These deficiencies mostly lie in the perception capabilities. For example, users who cannot see or hear as well as other require special consideration during the implementation of user interfaces." (Thomas Mandl, "Automatic Quality Assessment for Internet Pages", 2008)
"The degree to which a system is usable by as many people as possible without modification and is characterized in terms of the ability of users to have physical access to the system, the nature of users’ interface with the system, and the ability to physically retrieve potentially relevant information." (Deepak Khazanchi, "Information Availability", 2009)
"Making system resources available to a wider user community regardless of their geographical locations or the physical capabilities of their access devices." (Heba Kurdi & H S Al-Raweshidy, "Taxonomy of Grid Systems", 2010)
"The quality of a system incorporating hardware or software to engage a flexible, customizable user interface, alternative input and output methods, and greater exposure of screen elements to make the computer usable by people with cognitive, hearing, physical, or visual disabilities." (Microsoft, "SQL Server 2012 Glossary", 2012)
"The design of information systems such that they can be used by everyone, regardless of their ability or disability." (Julius T Nganji, "A Disability-Aware Mentality to Information Systems Design and Development", 2018)
"Any product, service, technology or environment is accessible and available to everyone, including individuals/learners with special needs." (Sunagul Sani-Bozkurt, "Universal Design Principles and Technology-Supported Learning in the Digital Era", 2019)
"In the learning object sense, ensuring that all information is versioned in multi-perceptual ways for the broadest available human use (for example, image information is made available in text format, which is machine/screen reader- and human-readable)." (Shalin Hai-Jew, "Methods for Analyzing and Leveraging Online Learning Data", 2019)
"Requirement that characterizes projects, objects, device, services, settings, easily usable by every kind of user. In particular, it refers to the possibility for an individual with motorial, perceptive, and/or psychical disability to approach public services and cultural initiatives in conditions of safety and independence, in order to remove the so-called 'barriers', both architectural and perceptive, that represent the obstacles for an equal public dimension, that respects disabilities." (Cecilia Cecchini & Miriam Mariani, "Exhibit Design for Architecture: A Non-Digital Method for the Inclusive Communication of an Architecture", 2019)
"The concept used to describe the degree to which practices and environments are able to be understood and utilized by people of differing abilities." (Kathryn R Green & Steven Tolman, "Equitable Means Accessible: Using Universal Design for Learning and Student Development Theory to Inform Online Pedagogy", 2019)
"Extend to which a person can access and use an object, reach a place, or obtain a service." (Sandra Sanchez-Gordon, "Striving for Inclusion in E-Learning and E-Health", 2021)